1. Field
This invention relates to gas and combustion fired turbines with compressor fans and housings. More particularly it pertains to a two stage compression combustion turbine with a turbocharger compressor associated with the air inlet. It employs curved radial sloping impeller blade compressor units, which initially densify the air before entering an optional further peripheral compression or collection chamber. This compressed air is then directed into the combustion chamber of a turbine. Alternatively, the turbocharger compressor may be located within the turbine exhaust gas stream to convert the energy in the gas stream leaving the turbine into rotational energy. It is particularly suited for use with jet engines.
2. State of the Art
A number of turbocompressors for natural gas fired or combustion turbines, such as the high altitude jet engine of Serriades, U.S. Pat. No. 3,260,046, are known. Lieu, U.S. Pat. No. 5,344,737 discloses an impeller disc vane design with tapered blades to compress gas passing through the crossover duct within the compressor section. Treager, in Aircraft Air Turbine Engine Technology, 1970 by McGraw-Hill, Inc. also discloses an impeller disc vane design with tapered blades to compress gases between the blades. These references do not have a plurality of stacked radial fan blades surrounding a central interior air intake area to function as a centrifugal fan. Lysholm, U.S. Pat. No. 2,244,467 discloses a radial turbine blade design with a central intake area for gases directed therethrough, but does not disclose curved blades with diminishing heights toward the perimeter to compress these gases. Cali, U.S. Pat. No. 3,265,290 discloses an axial flow compressor for jet engines, wherein the weir between the fairing and stator section is eliminated. Rosman, U.S. Pat. No. 3,945,101 discloses a rotor wheel for radial-flow fans and turbines with a center entry area. Fujino, U.S. Pat. No. 4,224,010 discloses a multi-stage turbocompressor with diagonal-flow impellers. Bachl, U.S. Pat. No. 3,226,085 discloses a rotary turbine with an axial flow component with a tangential flow path. O""Connor, U.S. Pat. No. 4,995,787 discloses an axial flow impeller with blades having a pronounced curve design. Wosika, U.S. Pat. No. 4,435,121 discloses a radial impulse turbine having low and high pressure sections. Teshima el al., U.S. Pat. No. 4,274,804 discloses an axial flow turbine with a helical flow path generated and used within the turbine. Seippel el al., U.S. Pat. No. 3,953,148 discloses a configuration of the last moving blade row of a multi-stage turbine, which is dramatically twisted. Pauly, U.S. Pat. No. 5,741,123 discloses a turbocharger compressor fan and housing for use with diesel engines, marine engines, combustion engines, and high altitude aircraft engines. Wislicenus, U.S. Pat. No. 2,395,704 discloses a water pump with curved blades, which is unsuitable for use as a high speed compression combustion turbine.
Of general interest is Quinn, U.S. Pat. No. 5,328,333, which discloses a rotating thrust producing apparatus employing circular foils for producing thrust in an axial direction when rotated.
The invention described below provides a centrifuge compressor combustion turbine with a turbocharger employing a series of compressor units employing curved impeller blades with radially diminishing cross sections to optimize gas collection, rotating thrust and gas densification.
The invention comprises a centrifuge compressor combustion turbine heat engine in which fuel burns to heat compressed air and the hot air and waste gases to drive a turbine. It employs a series of stacked compressor units having curved fan blades to optimize air collection and rotation densification. These blades not only gather intake air, but compress it between diminishing longitudinal cross sections flow channels between the blades, which may be downward sloping from their inlets to their outlets, or have walls of increasing thickness to radially decrease the cross sectional areas between blades to compress gases as they flow therebetween. After initial blade compression, the air may be further densified in a peripheral compression chamber. These compressor units thus function as a turbocharger and are generally positioned within the inlet air intake. They comprise a curved radial blade compressor system, which simultaneously collects and densifies the air before being further compressed in a peripheral compression chamber before entering a natural gas fired or combustion turbine. Alternatively, the compressor units may be placed after the turbine exhaust to collect the exhaust stream of a natural air or combustion turbine to convert the exiting gas energy into rotational energy.
The centrifuge compressor combustion turbine comprises a turbine frame defining air intake and exhaust openings. A diffuser section is attached to the turbine frame proximate the air intake having a plurality of compressor units. Each compressor unit has a housing defining a central air inlet leading into a peripheral compression chamber having compressed air outlets leading into a compressed air collection chamber. The compressor units are interconnected and operably associated with a turbine drive shaft rotatably mounted within the turbine frame. The drive shaft also supports a combustor section to burn fuel to heat the intake air to drive a fan turbine located on the drive shaft behind the diffuser section. The compression chamber has rotatably mounted therein with seating structure a plurality of interconnected stacked compressor units, each having an impeller attached to a rotatable circular impeller disc drive base. Each impeller disc drive base defines an opening surrounding the central air inlet opening, except for the last, which is covered and attached to the shaft.
In one preferred embodiment, a plurality of curved spaced radial sloping impeller blades having greatest height proximate the central air inlet and least height proximate the air outlets. They are attached to the top of each drive base forming sloping diminishing cross sectional air flow channels between the blades and housing cover. The impeller blades define impeller blade flow channels with air inlets in communication with the central air inlet. The impeller blades also define air outlets in communication with the air collection chamber to direct compressed air into the turbine combustor section. When connected and stacked, the compressor units form an open topped air intake in communication with the central air inlet of each impeller drive base so that the impellers rotate in unison and each air inlet is in alignment and communication with the next successor air inlet. A diffusion disc covers the last air inlet opening, and is attached to the turbine drive shaft with securing means to rotate the compressor unit impellers. The number of the compression units is selected to provide the desired compressed volume throughput into the turbine combustor section.
Thus, the plurality of stacked interconnected impeller compressor units surround and rotate about the central air inlet. The compressor units direct compressed air into the turbine combustor section wherein fuel burns to heat and expand the gases to turn a turbine. The open top of the stacked compressor units is rotatably attached to and in communication with the inlet opening in the frame, when the turbocharger is mounted before the turbine compressor section. Each impeller is mounted and seated to the rotating base of each compression unit such that each impeller is positioned to be in communication with its respective air inlet. A similar compressor system may be employed within the exhaust to convert the energy in the gas stream leaving the turbine into rotational energy.
Preferably, each impeller has a circular drive base impeller disc defining a central opening, which is attached to and surrounds the air inlet opening of the cylindrical support structure. A plurality of curved radial fan blades is then attached to the drive base surrounding the central opening. The curved radial fan blades are mounted on top of the drive base and structured to define air inlets therebetween. The inlet openings are optimally sized to capture a large volume of air from the air inlet. The air is then directed between diminishing flow channels defined by the radial blades for compression there between. These radial blades define an open top and a covered bottom when attached to the drive base. The air inlet opening is aligned and in communication with each respective housing air inlet.
Each fan blade thus defines air inlets leading into diminishing cross sectional channels between the impeller blades and out compressed air outlets therebetween. A frame cover covers the open topped impeller blades to form compression chambers between the blade segments. Compression results in the first preferred embodiment by progressively lowering the height proximate the inlets and cross sectional area between each blade until it is the lowest proximate the blade outlet. The compressor blades have a sloping surface starting with the greatest height proximate the top of the air inlet and diminishing as they extend radially there from in a curved radial sloping wheel configuration such that each impeller fan blade curves away from the disc""s direction of rotation.
In the second preferred embodiment, the radial blades have a constant height, but the blade walls have radially increasing thicknesses to progressively narrow the flow channel between the blades from the air inlet to the compressed gas air outlet to similarly compress gases flowing therebetween. Other geometric configurations providing radially curved or combination straight and curved segmented blades may be employed provided they have progressively narrowed flow channels between the blades from the air inlet to the compressed gas air out Net to compress gases flowing therebetween.
The angle of curvature of each blade at the fan blade outlet is the same as that at the inlet to minimize inlet flow losses. Thus, in the first embodiment each compressor blade segment has an inner elevated leading edge and an outer lower trailing edge so the height of each compressor blade decreases from the leading edge to the trailing edge to form with the drive base surface air flow channels, which are covered by the frame cover. As the impeller blades rotate, gases pass through airflow channels of diminishing longitudinal cross-sections to be compressed and directed out compressor air outlets. The dimensions of the diminishing flow channels and air outlets are selectively reduced in cross-sectional area to form the desired compression ratio. For example, an eight inch rise in the inlet opening, and a air outlet opening of xc2xc inch results in a compression ratio of 30 to 1. A four inch rise in the inlet opening, and a air outlet opening of xc2xc inch results in a compression ratio of 8 to 1. Once the compression ratio is selected and the impeller design structure determined, the number of the impeller compressor units is selected and stacked and fastened together such as by welding, fastening devices, or an outside threaded ring to provide the desired flow through of compressed gases into the turbine combustor section.
In one preferred embodiment, the centrifuge compressor blades should be capable of producing 100 psi before ignition. When turning at 20,000 rpm with a 20 inch to 40 inch diameter radial impeller, every square foot of flow has 144 square inches times 100 psi giving, 14,400 pounds of thrust before ignition. After ignition and expansion, this thrust should be increased by a factor of twenty times to produce 288,000 pounds of thrust per square foot of exhaust. This is three times that of any unclassified jet engine. However, the actual thrust will vary depending upon the rpms, the blade design, and the initial compression.
The frame defines a peripheral compression chamber compressed gas collector reservoir, which surrounds and is in communication with each impeller air outlet to collect compressed air accelerated by the impeller to slow the air down to convert air velocity energy into increased pressure densified air and direct it into the air turbine combustor section. The geometry of the compressions chamber gas collector reservoir may be structured to further increase the pressure of these compressed gases by forcing them through a smaller cross sectional outlet before entering the turbine combustion chamber. Conversely, if attached to the turbine drive shaft and placed to collect turbine exhaust gases, these compressor units act to collect the air flow exhaust energy and convert it into rotational energy.
One preferred layout of the curved impeller design has the blades of the impeller curved on an initial cord of sixty degrees, which allows for maintaining the distance between the blades at a constant distance from the center of the impeller to its outside edge, thereby maintaining the pressure while reducing the turbulence of the air. This is accomplished by dividing the circumference of the outer circular impeller blade drive base into 10 degree segments. Four equidistant concentric circles are then drawn with diminishing radii to serve as layout guides. The first blade circular shape is then drawn by connecting a series of intersection points of the 10 degree radii with the inner, outer and four equidistant intervening concentric circles with a French curve. The first point is the outer circle intersect at the 60 degree segment. The second point is the fourth inner concentric circle intersect with the 50 degree segment. The third point is the third inner concentric circle intersect with a 30 degree segment. The fourth point is the second inner concentric circle intersect with the 20 degree segment. The fifth point is the first inner concentric circle intersect with the 10 degree segment. The sixth point is the inner circle intersect at the 0 degree segment. These six points form the extended radial edge of the outside edge of the impeller blade proximate the air inlet, which gradually changes in curvature toward the outside edge of the impeller blade proximate the air outlet. The next circular blade is then drawn parallel to the first blade starting from the width of the inner blade opening between the adjacent blade, and ending 60 degrees from its extended radius of the edge of the next inner blade.
The number of concentric circles for a layout is dependent upon the diameter of the impeller. More concentric circles and intersection points are needed as the diameter increases in size larger than shown for the above example.
Another preferred embodiment has blades with radially increasing in thickness walls, which are not equidistant apart, but form gradually diminishing width flow channels to further compress the air through diminished width as well as height air outlets. Various curvilinear (combination straight and/or curved segments) blade shapes may be employed, but they must have the same diminishing flow channel relationships and preferably have the trailing edge to intersect a 60 degree chord with the extended radius of the impeller blade leading edge.
The exact layout may be employed by connecting by hand intersecting curves, or via a computer auto cad program, which uniformly spaces the distances between the blades and insures that they intersect a 60 degree chord segment between an extended radii of the inner blade edge and the point of contact with the outer blade edge.
The impeller may be made from a cast titanium slug with a center inlet air opening and slots for the cover machined to specification. A computerized milling machine is then programmed to cut a cord of 60 degrees between each blade making the spacing between the blades equally spaced from the inlet to the outlet of the impeller to form a one piece construction with the back of the impeller laid flat on the milling machine. The height of each impeller in the sloping blade preferred embodiment is preferably not higher than four inches at the highest interior point proximate the inlet, and thereafter gradually sloped to a desired height proximate the outlet to provide the desired compression ratio. An impeller blade cover is then assembled around. the impeller to form a compression unit with a compressed air outlet by machining a raised peg off each blade on top. The impeller blade cover would then have slots made to correspond to the raised pegs. The next process would be to use the spaced metal used to rework the shafts. Next the upper cover is machined and acts to support the next compressor unit while sealing the moving air within the blade channels. This cover also secures to the upper portion of the blades of the impeller, and thus sealed forms an individual compression unit. A plurality of compression units is then assembled as discussed above to provide the desired air compression and flow requirements.
Although the invention is designed primarily to be operated such that the blades curve in the direction of rotation of the circular drive discs, the compressor units may be operated in reverse so that the impeller blades curve opposite the direction of rotation. This mode of operations thrusts the compressed air by mechanical force in addition to centrifugal force.
The invention thus provides a new centrifuge compression combustion turbine configuration, which compresses and directs high volumes of compressed air into the combustor segments of fuel fired or combustion turbines. Compression is accomplished in two stages. First by forcing inlet air through diminishing flow channels between impeller blades to blade compress the air. Second, the blade compressed air may be further compressed in a geometrically restricted peripheral compression chamber collecting the blade compressed air forcing it through a restricted path for further compression before being directed into the combustion chamber.
Alternatively, the compression units of the centrifuge compression turbine can be placed within the turbine exhaust stream to convert gas flow energy into added rotational energy.